What is the AI Content Detector?
No AI content detector — including this one — can reliably prove whether a specific piece of text was written by AI. This tool does not attempt to. Instead it measures four statistical writing-pattern signals directly from your text: sentence-length variance (burstiness), vocabulary diversity, repetition of transition phrases over-represented in AI-assistant writing, and punctuation-pattern uniformity. Each is a genuine, computable statistic — a standard deviation, a ratio, a phrase count — shown with the exact method used to calculate it. None of them, alone or combined, is evidence that a person did or did not write something, and this tool never outputs a single "% AI-written" score, because that number would be fabricated confidence dressed up as a measurement.
The most important limitation to understand before using this tool: false positives disproportionately affect non-native English writers. Sentence-length variance and vocabulary diversity both tend to be lower in the writing of people composing in a second language, for reasons that have nothing to do with whether AI was involved — simpler sentence structures and a narrower working vocabulary are a normal, well-documented feature of non-native writing at every skill level. A detector that flags "low burstiness, low vocabulary diversity" as suspicious will systematically flag non-native writers more often than native ones, regardless of who actually wrote the text. Never use this tool's output to accuse a student, colleague or contributor of using AI — it is not evidence, and treating it as evidence causes real harm to real people.
An honest note on the data
No AI detector is reliable enough to accuse anyone. This tool reports statistical signals (burstiness, perplexity proxies) as indicators only.
Why use a free ai content detector?
Four named, measurable signals — not a black-box score
Burstiness, vocabulary diversity, transition-phrase density and punctuation uniformity are each shown with the exact statistic and formula behind them, so you can see precisely what was measured.
No fabricated "% AI-written" number
The tool deliberately does not output a single probability or percentage, because no defensible calculation for that number exists without ground truth this tool cannot have.
Explains the false-positive risk up front
The tool states plainly, before you even see a result, that these signals systematically misfire on non-native English writing — a limitation many detectors do not disclose.
Shows the sentence-length pattern visually
A bar chart of every sentence's word count makes burstiness (or the lack of it) visible at a glance, rather than reducing it to an opaque single number.
Runs entirely in your browser
All four calculations happen locally — nothing you paste is sent to a server or an AI model to be analysed.
How do you use the AI Content Detector?
- 1
Read the warning first
Before pasting anything, understand what these signals can and cannot tell you — they are not proof of authorship, and false positives are common, especially for non-native English writers.
- 2
Paste the text to analyse
Results update automatically. Longer text (several paragraphs) gives more statistically meaningful sentence-length and vocabulary measurements than a single sentence.
- 3
Review each of the four signals individually
Each panel shows the measured value, a low/medium/high label, and the exact method used — read the method, not just the label, before drawing any conclusion.
- 4
Treat the result as a prompt for discussion, not a verdict
If a signal looks unusual, the appropriate response is a conversation with the writer about their process, not an accusation.
How accurate is it?
Every number shown is a directly computed statistic from your text, not a model prediction: burstiness is the coefficient of variation of sentence length (standard deviation ÷ mean), vocabulary diversity is a type-token ratio (unique words ÷ total words), transition-phrase density is a literal count of specific phrases per 100 words, and punctuation uniformity is the coefficient of variation of commas per sentence. All four are calculable with certainty. What is not certain — and cannot be made certain by any tool — is what any combination of these numbers means about who or what wrote the text.
- Burstiness: standard deviation of sentence length ÷ mean sentence length, across every sentence in the text. Human writing that mixes short, punchy sentences with long, complex ones scores higher; uniform sentence length scores lower. Careful human editors who write consistently will also score low here.
- Vocabulary diversity: unique words ÷ total words (type-token ratio). A technical piece that deliberately repeats a key term will score low on this measure for entirely legitimate reasons.
- Transition-phrase density: a count of phrases over-represented in AI-assistant writing ("moreover", "in conclusion", "it is important to note", "plays a crucial role" and similar), normalised per 100 words. Formal academic and business writing also uses many of these phrases naturally.
- Punctuation uniformity: coefficient of variation of commas per sentence, plus how many distinct terminal marks (., !, ?) appear across the whole text. A narrow, repetitive punctuation rhythm is measured, not explained.
- None of these four signals were validated against a labelled dataset of confirmed AI-written and confirmed human-written text by this tool — they are general, published stylometric measures, applied honestly and shown with their exact method, not claimed as a trained or calibrated detection model.
What should you know before using it?
What each signal label means, and how much weight it should carry:
| Signal | What a "low" or "high" reading actually indicates |
|---|---|
| Burstiness (low) | Sentence lengths are unusually uniform. Common in some AI writing, but also in formal, tightly edited or non-native English prose. |
| Vocabulary diversity (low) | A narrower range of distinct words relative to text length. Common in technical writing, short texts, and non-native English writing. |
| Transition-phrase density (high) | Frequent use of phrases like "moreover" or "in conclusion". Also common in formal academic and business writing styles taught explicitly in many non-native English curricula. |
| Punctuation uniformity (high) | A consistent comma-per-sentence pattern and narrow use of terminal punctuation. Also typical of careful, rule-following editing. |
Which tools relate to the ai content detector?
The ai content detector is one of 12 writing tools on this site. These are the ones most often used alongside it — either because they handle the next step in the same job, or because they answer a question this tool raises.
Plagiarism Checker
A related but different question — this checks writing-pattern statistics, not similarity to other sources. Neither tool proves who wrote a text; use both cautiously and never as standalone evidence.
Readability Score Checker
Sentence length feeds both readability formulas and the burstiness signal here — a text with genuinely varied, well-edited sentences will often score well on both.
Sentence Checker
Flags individual sentences that are unusually long, short or run-on — useful context for understanding why a burstiness score came out the way it did.
Online Proofreader
If transition-phrase repetition is flagged, this tool can help you vary the actual wording — a separate concern from whether the phrase itself is a meaningful signal.
When should you use a ai content detector?
Because the ai content detector runs entirely in your browser, it suits work you would not want to hand to a third-party server — client files, unpublished drafts, anything under an NDA. These are the situations people reach for it in most often.
Reviewing your own writing before publishing
Check whether your own draft leans heavily on flagged transition phrases or reads with unusually uniform sentence rhythm — useful for improving style, independent of any authorship question.
Starting an informed conversation, not an accusation
If a piece of writing looks unusual, use these signals as a prompt to ask the writer about their process — never as standalone grounds for a disciplinary or academic-integrity decision.
Editing AI-assisted drafts for a more natural rhythm
If you used an AI tool as a starting point and want the final piece to read less uniformly, the burstiness and transition-phrase panels show you concretely where to vary sentence length and wording.
Understanding detector limitations before relying on any tool
Use this page's explanation of false-positive risk as a reference before trusting the output of any AI-detection tool, including commercial ones that present a confident-looking percentage.
Frequently asked questions
Can this tool prove whether text was written by AI?
Why doesn't it give me a percentage, like other AI detectors do?
Does this tool discriminate against non-native English writers?
What is "burstiness" and why does it matter?
What are the "transition phrases" it looks for?
Should I use this to grade student work or accuse someone of using AI?
Is my text sent to an AI model to be analysed?
Is the ai content detector safe to use?
This tool runs entirely inside your browser. Your text, files and settings are processed on your own device and are never uploaded to our servers — there is nothing for us to store, log or leak. You can confirm it yourself: open your browser DevTools, switch to the Network tab, and use the tool. You will not see an upload request. It also means the tool keeps working if your connection drops mid-task.
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